Time-controlled heating device



Oct, 17, 1933. Q WELLS 1,930,703

TIME CONTROLLED HEATING DEVICE Filed Feb. 9, 1951 3 Sheets-Sheet 1 INVENTOR. [0/"/ J We//5 BY WIZ r% Oct. 17, 1933, E. J. WELLS TIME CONTROLLEDHEATING DEVICE Filed Feb. 9, 1931 3 Sheets-Sheet 2 INVEN TOR. [ar/ J.Wz//5 6 a aim 3 A TTORNEYS.

Oct. 17, 1933. J WELLS 1,930,703

TIME CONTROLLED HEATING DEVICE Filed Feb. 9, 1931 3 Sheets-Sheet 3 i7 i653 a/ a/-- 77 73 77 76 7a a2 a2- 63 z 4a y I\\ I J .L

5 a/ a3 73 i/ I 77 76 7a I INVENTOR.

z; 74 9/ /6 I a? [Or/J /Vz//5 BY 79 I ATTORNEYS.

Patented: I Oct. ,1 7, '933 TME-GONTROLLED HEATING msvlca Y Earl J.Wells, Alameda, Calif.

Application February 9, 1931; Serial nogsiigis,

f 4 Claims. 101. 200-138) invention relates to as. controlled hea t.

1m devices andis particularly applicable to electrical heaters. C v 1fe'ountly it is desirable to operate electrical heating apparatus sothat a predetermined heat ing'eflect is produced during. a definitetimein-f terval and a different heating effect is produced outrocesseswherethe time of operation and h smp ra u a bot ,v i o a is ageneral object of 'rny invention toprode an automatic .timef controlledheater 'of 'novel'constructionl successive time intervals.

of l the heater t difielrent temperatures during Another object is toprovide shovel timing device' suitable for use in a heater of the char-.acterjdescribed. j a A further object is toprovidea novel heatingelement in "a: device of the character detia lly uniform over the entirearea of the element irrespective of whether it is operating ata high orlow temperature and in which theuse I 01 separate resistance elernentsis eliminated.

character described in which i the control of the time of operation andof theam ountof heat. is entirely automatic after the device has beeninitially set inoperation.

" 'Iheseand'ptherobjectsand advantages are the principles ofmy-invention. v

Fig. 2 is a'plan view of .the device shown in Fig.1.: H

3 is across section of the timing apparatus of the device taken'valongline 3+3 of Fig.4 is across section taken on line 4- --4 of Fig. 5 isacross sectional [view takenon line 5-5 of Fig. 3, illustrating theconstruction of trol'of'the operation of a heater isobjection-p nother.object 'is toprovide-an electrical heat ;er having means for controllingthe operation 'nite levelin the governor.

scribed in; which theheating effect is substam' A further object is toprovide a heater of the .Fig. 1 is an elevational view of an electrical.furnace, suitable for use in laboratories, embody? a preferred form ofgovernor for thetiming-ap-y paratus, Fig. 6 is a cross sectional viewtaken on line" 6 6.ofFig.'5. e

Fig. 7 is afragrnentary view of the governor shownfin Fig. 5illustrating the" flow of certain mercury in thegovernor during theoperation thereof m 1 I Figs. 8,. 9, 10 and l1 are views, partlydiagrammatic, illustrating the operation of certain timing disksemployed in the device.

Inits preferred form the invention comprises an electricalheaterprovidedwith a ti'ming device' for. automatically controlling the time ofoperation and the temperature of the heater. The timing device iscontrolled bya governor. which in its preferred form, comprises arotatable'member having a. chamber therei'n in which a quantity ofmercury is placed and "is" constructed with a labyrinthineobstructionwithin i the chamber so that the gravitational flow of themercuryis retarded. Means can be provided for rotating the governor 1and preferably the force tending to effect-rotation .is such that-itcannot overcome. the retarding effect of the mercury .unless themercuryflows below a defi- Thus. the rate of rotation of the governor isdependent not only. upon the driving force but also upon the rate offlow of the mercury'. Means can also be provided for changing theelectrical connections in the heater circuit after a, definite time interval to change the heating effect of theheater. In the embodimentillustrated in the drawings, ,I have. shown a furnace 'which is suitablefor 1 use in dental laboratories, but it is to be understood that theprinciples of the invention eanbe applied to other types of electricalheating devices. l r Referring now to the drawings, l ha ve shown a timecontrolled heating device comprising a furnace l6 and a timing device1-7 both of which can be mounted. on a suitable base 18. i Thetimingdevice. 17 is provided with a suitable'housing and comprises a'clock-work mechanism.- 19 and a governor -21 which is adapted to be driventhereby. In the embodiment illustrated the clock-workmechanism is drivenby a. coil spring 22 having. one end 23 thereof secured to theffra'mework and the other end secured to a shaft .24 on which is fixed agear 26.. .Gear 26 .mesheswith apinion Z'Tand rigidly secured to theshaft .28 of the pinion 2'7 is a ratchet wheel 29. ,Loosely'rnounted onshaft 28 is a gear 31 carrying a spring biased pivoted so" i pawl 32which engages the teeth of the ratchet wheel 29. Gear 31 in turn mesheswith a pinion 33 secured on the governor shaft 34.

Thus, when the spring 22 is tensioned a force is applied to the governorshaft 34 through the train of gears forming the clock-work which tendsto impart rotation to the shaft 34. The ratchet wheel 29 serves totransmit the force of spring 22 to the governor on the unwinding of thespring, but enables the spring to be wound or tensioned without rotatingthe governor shaft 34, the teeth of ratchet 29 slipping past the pawl 32as the spring is being tensioned.

For tensioning the spring 22 an operating lever 36 is provided which ismountedin apertured ears or projections 37 and 38 secured in anysuitable manner to a disk 41 loosely carried by a shaft 39. Theoperating lever 36 is preferably longitudinally slidable in theapertures in ears 3'7 and 38 and can have secured thereto a collar 42which serves as an abutment for spring 43 extending between the collar42 and the ear 38 to bias the lever 36 in the posi tion shown in Fig. 4.

Rigidly secured to shaft 39 is a second disk 44 -making frictionalengagement'with the disk 41. A gear-46 which can be formed integrallywith the disk 44 'or otherwise mounted to rotate therewith is providedwhich meshes with a pinion- 4'7 fixed to the shaft 24 to which one endof the spring 22 is connected. For operably connecting lever 36 to thegear 46, a projection 48 mountedon gear 46 extends into the path oflever 36 as the latter is moved in a clockwise direction, as viewed inFig. 4. Thus, upon movement of the lever 36 in a clockwise direction,

the spring 22 is tensioned through the medium of gears 46 and pinion 47meshing therewith. Rotation of pinion 47 effects rotation of shaft 24and the gear 26 thereon which in turn meshes "with pinion 27 to rotatethe ratchet wheel 29.

' densate product, and,

The rotation of'ratchet 29 during the tensioning of the spring is in aclockwise direction, as viewed in Fig. 4 and during this movement of theratchet the teeth thereof pass under the pawl 32, as hereinbeforementioned.

The disk 41 has a notch 51 in the periphery thereof and a somewhatsimilar notch 52 is provided in disk 44. A bell crank lever 53 pivotedabout a pin 54 has one arm 56 thereof normally extending into thenotches 51 and 52 of the disks and clockwise rotation of the disks 41and 44, therefore, is normally restrained. To remove the restraint,lever 36 ismoved longitudinally against the force of spring 43, wherebythe end 57 of the lever 36 abuts against the arm 56 and removes it fromthe notches 51 and 52. While the arm 56 remains depressed, the lever 36can be swung in a clockwise direction, carrying with it both of thedisks 41 and 44 and also the gear 46, thereby tensioning thespring.

The energy thus stored up in spring 22 is expended in moving the variousparts of the timing mechanism and mainly in impartingrotational'moveme'nt to the governor 21. The governor 21 is secured tothe shaft 34 to rotate therewith and is preferably'of generalcylindrical shape, as illustrated in Figs/5 and 6. For convenience thegovernor can be made of suitable moldable material, such as a, phenolicconif desired, can be made in two parts, one part including the sidewall 61 and the peripheral wall 62 and the other part being in the formof, a flat disk 63, serving as the other side wall.

.side walls 61 and 63, thus forming a plurality of compartmentsor stallsopening into the center of the governor.

A quantity of mercury 68 is placed within the chamber and normally flowsto the position shown in Fig. 5 when the governor is at rest and tendsto assume this position when the governor is rotating. For enabling themercury to flow from one of the stalls to an adjacent stall, the wall 63has formed therein a groove 69 communicating with adjacent stalls andthrough which the mercury can flow. In the embodiment illustrated, thegroove 69 is annular in shape for convenience in manufacture, butifdesired any other shape of groove or any num-f: ber of grooves or otherpassages can be provided for forming a leakage path between adjacentstalls for the flow of mercury. In this manner a labyrinthine path isprovided for retarding the flow of mercury as it seeks the lowest levelwith-1 in the chamber. The flow of mercury is thus confined to a pathextending along one side of each of the-partitioning members 64 andthrough the passage formed by groove 69. 4

The rotation of the governor when driven by. the spring 22 is preferablyin the direction of the arrow in Fig. 7. Assuming that the governorisinitiallyat rest and the mercury 68'is at the level illustrated in Fig.5,. a force tending to rotate the governor in the direction of the arrowin Fig. 7 will cause the mercury to be carried to Assuming further thatthe force is insufiicient to carry the mercury the level shown in Fig.'7.

to a higher level, the governor. will remain at. rest at the positionshown in Fig. 7.;as long as the mercury remains at this level, acondition" of the arrow. The rate of rotation of the gover-.

nor is thus determined by the rate of flow of the mercury and by makingthe groove 69, or other passages which may be provided, larger orsmaller in cross section, the rate of rotation can be correspondinglyvaried provided the force exerted by the spring 22 remains constant.

Preferably, the governor 21 is mounted for rotation about asubstantially horizontal axis, as illustrated, and the channels '71formed at the intersection of the partitioning members 64 with' theinterior peripheral wall 72 can be sloped to direct the flow of mercurytoward the groove 69. The interior wall 72 and each of the otherclinedioinduce the-flow of" the mercury toward thewgroove '69, therebyinsuring complete re-J moval oi the mercury-1mm each stall beforeit'isii movedato'the uppermost position. However,

into the stalls on the right; hand side of the governor, as viewed inFig." 5, thereby'retarding the rotationoi the governor and tendingtocormet the .error which might have been caused in the :timeofoperation had the mercury :been perinitted to bexcarried over to theleft ,hand .side

i of the governor.

Diirlngw the rotation oft he governor 21, the

shalt" 24 rotates relatively slowly and the" pinion 47 thereonimpartslrotation to the gear 261and thedisk 44flThe rotation of disk 44is in a direction opposite to thatinwhich it was rotated during; thetensioning of the spring and as the t disk 44rotatesjit carrieswith itthexdisk fll wlth which it is frictionally 'engaged' Eventually thenotches 1'; and 52in the'diskswill be restored'to the s'tartingpo'sition adjacent the end 56 otthe interval required to! this restoringmotion-to -eflect timing of the apparatus; o l I "I'he' other end 73 ofthe bellcrank lever 53' isflplvotally connectedas at-74 to a rod '76which isprovided 'with a bifurcated contact member "77 at oneend. Rod'16 'is'normally urged to the right as viewed in Fig. 11 bya spring '18which 'thereb "serves to bias" the linkage mechanism "s mmered contactmember 77 coop rateswi th-a group offixedcontacts 81, 82"

i afnd83"*arranged substantially as' shown in Figs. 31 11; to form athree-pole switch. The positlon of the arm 56 of theybellcrank lever 53contr heating coil the portion" of the bifurcated contact member f'land-is adapted to move the contact member to three distinct positions,so that it bridges contacts 81 an'd 82 in one of its positions,

contacts 81 and 83 in the second position and in the thirdpositlon bothlegs of the bifurcated contact member rest on contact83, [The con;

,. tacts 81,18 2 and 83 "can be connectedin a circuit witht heelectric'al heating device 16, substantially as's'hown in Fig. 1o,-tocontrol the current suppl edto the'heating device fromsupplylines 86 and87. "One side of the line can be connected to a, contact 88 whichengages one, endol the o! theheating device lfi and the contactsazandfiacan be connected to connect-,

4 to the circuit, the heating"device joperates at a? device v Assumingthat whenrthegpart of the heatingvplugs 8 9 and191"which"are adapted tobe [to intermediate taps'on the ,heating n e IQ coil' between plug ,89and contact 88 is connected as temperature andthat whenfthe part, of theh coil betweentap 9l and contacthBS is; connected to the circuit, thedevice operates at a higher temperature the heating device willbeoperatb at a-relatively low temperature when the contact 7'7 bridgescontacts 81 and 82 and will be.- operating at ahigher temperature whenthe contactsiil and 83 are bridged.bThe arrangeinf nt' or the parts issuch that when the. bellsurface; of'disk 44, howevenjthe contacts 81 and83, are bridged, thereby connecting the device for should anyimercury bychance be carried to the uppertpart of the governor, thelshape of the.partitioning walls causes the mercurys'dropping trolrrone of theuppermost stalls to be deflected operation at the higher temperature.If, on the. other'hand, both notchesfil ands 52'of thev'disks arecoincident and the bell crank leverf53 has entered both notches, asshown in :Fig. .4, the.

oranyother time interval'and the scale can:

be placed adjacent a slot' 93 through which the actuating lever36'extends; The scale'is .calibrated in such a manner that when thelever. 36 movedto a definite position on the scale, to

tension the spring 22, the" notch52on disk 44 "will notbe restored tothe initialposition until the'ti'me indicatedxby the scale-1 has.elapsed, When the notch.51 indisk:41 isnot moved relative .to'the notch'52, notch 51will' also require the time indicated by the scale toreturn toiits gagement between disks-"41 and 44, however, the notches'51and 52' can be. adjusted to different positions, in whichevent adifferent time interval. will be required for the respectivelnotches'tobe restored to their: initial position.

is moved longitudinally againshthe arm 56 of: the b ellcrank lever 53,as shown in' Fig. .8. to, move the bellcrank lever.- outsotthecnotchesl51 and 52 and: the lever 36' is then" swung in a to any desired positionby thefoperator land by watching the; scale 92 the time of operation canbe fixedat any value. If for example, the lever when in the positionshown in Fig. 9 has been thus connecting the heating device ,foroperation atthelower temperature. When the bellcrank lever" 53 .restson.the peripheral lnzsetting the timing mechanism the-leverfi fi' clockwisedirection to a position'such :asthat illustrated in Fig.9. The lever 36can be moved moved to: the ten minute, positiononthe scale- 92,. thedevice-will operate for :ten minutes-v before both notches are restoredto the startingpoint'to disconnect the heater." A fixed stop 94 secured,in any suitable mann er to-the frame of thliimechanism extends intothepath of lever 36 and determines the normal starting, position of theapparatus. A

7 After the lever 36 hasbeen moved tothe position shown in Fig. :9andthe,lever.-released the disks will begin their movement back towardthe initial position under the. influence of spring 22 and governor 21;As heretofore described 'the disks 41 and44arein frictionalengagementwith one anotherand they therefore will move to-i getherduringthe restoringoperation. It i'sgnot essential however, thatthefnotches-bl -and;52 I

be in "unison during the restoring movement and ter-clockwise directionto an intermediate 'position. as illustrated in Fig. l0, therebyadvancing thenotch 52. Assuming that the lever whenit is in the positionshown in Fig 9;,c'oincideswith the ten minute graduation onethe scaleand; when if desired," the lever- 36 can be swung in la coun-g it is inthe position in Fig; 19 kit: indicates four,

for four minutes'at,=-a low temperatureand for minutes on'the scale,theheater will beoperated "a six minute interval immediately followingit will beoperated at? high temperaturgl at the end of. the six minuteinterval the device will be disconnected fromthe circuit,

From an inspection. of Fig. -10 it; will be seen that' the bellcranklever 53,,rests on the periphery of the disk 41 when the parts are inthe'position' shown. Now as disk is rotated it carries with it disk 41and the two will move in synchronism until the notch 51 reaches aposition adjacent the end of arm 56 whereupon the arm 56 will fall intothe notch 51 and rest on the periphery of disk 44, as shown in Fig. 11.Upon this movement the bifurcated contact member 77 is moved from theposition shown in Fig. 10 in which it bridges contacts 81 and 82 totheposition shown in Fig. 11 where it engages contacts 81 and 83, thuschanging the connections to the heating element from low temperatureoperation to high temperature operation. At this time the lever 36strikes theprojection 94, thus impeding any further rotation of disk 41.Disk 44 however, is not constrained in its movement at this time andcontinues its rotation for six minutes longer, in the example chosen,until the notch '52, is coincident with the end of arm 56. Arm 45thereupon enters both notches and the bellcrank lever 53 assumes theposition shown in Fig. 4, thereby moving the bifurcated contact member'77 to a position to disconnect the heat; ing device.

Thus, the device can be initially set to operate at a definitepredetermined period at one temperature and for a subsequent definiteperiod at another temperature. It is to be understood that the plugconnectors 89 and 91 can be reversed if desired so that the hightemperature is produced for the first period and the low temperature forthe second. An audible alarm, such as a gong 96, can be provided whichis adapted to be sounded at the end of the second period. Forconvenience, the striker 97 of the gong can be mounted for movement withthe bellcrank lever 53, so that as the end 56 of the lever moves intonotch52, the alarm will be sounded.

While I have shown and described a preferred form of my time controlledheating device, it is to be understood that I do not wish to be limitedthereto, since the invention as defined in the appended claims can beembodied in a plurality of other forms.

- I claim:

1. Timing mechanism for controlling the operation of electricalapparatus for successive time intervals, said mechanism comprising arotatable shaft, means for driving said shaft at a constant rate ofrotation, a circular disc mounted'on said shaft for rotation therewith,a second circular'disc loosely mounted on said shaft and frictionallyengaging said first disc, one of said discs being of greater diameterthan the other, each of said discs having a notch in the peripherythereof, the bottom of both notches being disposed at substantially thesame radial distance from said shaft, a pivoted lever having an armextending across the peripheral portion of both discs, means for biasingsaid arm in such a direction that it tends to enter the'notches insaiddiscs, setting means for adjusting said discs in any desired angularrelationship relative to each other, rotation of said shaft serving toadvance the notches in both discs toward said lever arm, whereby saidlever arm enters the notch in the larger of the two discs and rests uponthe periphery of the smaller of the two discs after a predetermined timeinterval, means for retarding the rotation of the larger disc when thenotch therein'is in the position of registry with the lever arm,continued rotation of the smaller disc serving to advance the notchtherein toward the lever arm, whereby after a predetermined timeinterval the lever arm entersthe notch in the smaller disc, and meanscontrolled by the movement of thelever arm from the periphery of thelarger disc to the periphery of the smaller disc and from the peripheryof the latter disc to the notch therein for controlling the operation ofthe electrical apparatus. 1

2. Timing mechanism for controlling the operation of electricalapparatus for successive time intervals, said mechanism comprising arotatable shaft, means for driving said shaft at a constant rate ofrotation, a circular disc mounted on said shaft for rotation therewith,a secondcircular disc loosely mounted on said shaft and frictionallyengaging said first disc, one of said discs being of greater diameterthan the other, each of said discs'having a notch in the peripherythereof,- the bottom of both notches being disposed at substantially thesame radial distance from said shaft, a pivoted lever having an armextending across the peripheral portion of both discs, means for biasingsaid arm in such a direction that it tends to enter the notches insaiddiscs, setting means for adjusting saiddiscs in any desired angularrelationship relative to each other, said setting means comprising alever carried by the larger disc, a projection extending from thesmaller disc into the path of movement of said setting lever when thelever-is moved in one direction, whereby both of said discs-are turnedin unison when said setting lever is moved in one direction, means forholding the smaller disc in its adjusted position, whereby said setting1ever can be moved in the opposite direction against the frictionalforce betweenthe two discs to move the larger disc relative to thesmaller disc, rotation of said shaft serving to advance the notches inboth discs toward said lever'arm, whereby said lever arm enters thenotch in the larger of the two discs and rests upon the periphery of thesmaller of the twodiscsfafter a predeterminedtimeinterval, means forretarding the rotation of the larger disc when the notch therein is inthe position of registry with thelever arm, continued rotation of thesmaller disc serving to advance the notch therein toward the :lever arm,whereby after a predetermined time interval the lever arm', enters thenotch in the smaller disc, and means controlled by the movement of the'leverarm from the periphery of the larger disc to the periphery of thesmaller disc and from the periphery of the latter discto the notchtherein for controlling the operation of the electrical apparatus.

3. Timing mechanism forcontrolling the operation of electrical apparatusfor successive time intervals, said mechanism comprising a rotatableshaft, means for driving said shaft at 185 a constant rate, of,rotation, a circular disc mounted on said shaft for rotation therewith,

a second circulardisc loosely mounted on said shaft and frictionally'engaging said first disc, one of said discs being of greaterdiameterthan 140 the other, each of said discs having a notch in the peripherythereof, the bottom of both notches being disposed at substantially thesame radial distance from said shaft, a pivoted lever having an armextending across the peripheral 145 portion of both discs, means forbiasing said arm in such a direction that it tends to enter the notchesin said discs, setting means for ad- Justing said discs in any desiredangular relationship relative to each other, rotation of said 150 shaftserving to advance the notches in both discs toward said lever'arm,whereby said lever 'arm enters the notch in the larger of the two discsand rests upon the periphery of the smaller 01' the two discs, after apredetermined time interval, means for retarding the rotation of thelarger disc whenthe notch therein is in'the po- 'sition of registry withthe lever arm, continued rotation of the smaller disc serving to advancethe notch therein toward the lever arm,;'wherei by after a predeterminedtime interval the lever arm enters the notch in the smaller disc, and

an electric; switch operative to three distinct positions in" responseto movement of said lever arm, each position of said lever armdetermining electricafappara us being underthe control of said switch. I

,one position of the switch, the operation of the 4'. Timing mechanismasdescribed in claimcl,

in which the'settingtmeans comprises a lever carried by the larger discfor effecting turning movement of said disc, one end of said lever be:ing disposed adjacent the notch in said larger against the force of thebiasing means associated with the lever arm.

EARL J. WELLS.

